Abnormal Tunnel Packages between 2 OVS

asked 2015-12-29 04:41:07 -0800

nevalosa gravatar image

updated 2015-12-29 04:48:00 -0800

There is GRE tunnel between 2 OVS(OpenStack Compute Node and Network Node), here is the tunnel on Compute Node OVS:

    Bridge br-tun
        fail_mode: secure 
        Port "gre-1e1e1e01"
            Interface "gre-1e1e1e01"
                type: gre
                options: {in_key=flow, local_ip="30.30.30.3", out_key=flow, remote_ip="30.30.30.1"}

And I add a flow to reply a ARP on Compute Node then Compute Node farword a ICMP Request to Network Node OVS. As you know, the ICMP Package should go thru the GRE tunnel and the package should be fromVTEP 30.30.30.3( Compute Node) to VTEP 30.30.30.1(Network Node), but the strange thing is that the source VTEP is 30.30.30.254(Gateway), tcpdump on Network Node OVS shows below

20:05:58.612370 IP (tos 0x0, ttl 63, id 34833, offset 0, flags [DF], proto GRE (47),th 126)
    30.30.30.254 > 30.30.30.1: GREv0, Flags [key present], key=0x33, length 106  <<= abnormal src ip
    IP (tos 0x0, ttl 64, id 48800, offset 0, flags [DF], proto ICMP (1), length 
    10.10.10.6 > 10.10.10.3: ICMP echo request, id 11553, seq 30850, length 64   <<= ping from VM

Route table on Compute Node OVS(eth2: 30.30.30.3, eth0:210.0.0.104):

root@compute:~# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         210.0.0.1       0.0.0.0         UG    0      0        0 eth0
20.20.20.0      0.0.0.0         255.255.255.0   U     0      0        0 eth1
30.30.30.0      30.30.30.254    255.255.255.0   UG    0      0        0 eth2
30.30.30.0      0.0.0.0         255.255.255.0   U     0      0        0 eth2
192.168.122.0   0.0.0.0         255.255.255.0   U     0      0        0 virbr0
210.0.0.0       0.0.0.0         255.255.255.0   U     0      0        0 eth0

and Network Node route table

root@network:~# route -n
Kernel IP routing tabl
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
20.20.20.0      0.0.0.0         255.255.255.0   U     0      0        0 eth1
30.30.30.0      0.0.0.0         255.255.255.0   U     0      0        0 eth2
210.0.0.0       0.0.0.0         255.255.255.0   U     0      0        0 br-ex

Could anyone help me please? Thanks in advance.

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